Barriss Offee was a female Mirialan Jedi Knight during the horribly drawn-out conflict known as the Clone Wars. Offee was paired with her depressive Master, Luminara Unduli. Offee was not as depressed as Unduli, being that she was an extremely gifted healer and had something to look forward to.
Several times, Offee's master abandoned her and left her for dead. Though she was always polite to Luminara's face, behind her back Offee was a conniving Padawan who planned to one day murder her master. Unfortunately, Order 66 beat her to it. Offee was hardly ever seen fighting. She mostly just stood around looking at everyone else. Her master never really gave her a chance to fight. Offee was known by clone troopers for her cold and distant attitude, like she thought she was better than mere clones.
Offee was also secretly jealous of Aayla Secura's beauty, and planned to kill her one day as well. Order 66 beat her to it, though, when Offee and Secura were stationed on Felucia. The clones happily torched Offee to smithereens by blasting her with an AT-TE, which was a bit of overkill, honestly. I mean, she was barely old enough to be considered a Jedi Knight.
Oh, and Offee secretly hooked up with Ahsoka Tano while on their mission to Ansion. Offee obviously had a bad experience at some Mirialan tattoo joint. I mean, check out those tats on her face. Maybe it was just a rebellious teenage thing against her master. Also, some wonder if Barriss was gothic. Check out that dark lipstick. Offee also had accidents a lot...there was the time she was kidnapped on Ansion. Or the time she "accidentally" injected herself with bota... we know you were addicted to that drug, Barriss. Or the time she cut her foot while practicing her lightsaber moves, which were very few, seeing that she hardly ever fought. Or the time she and Jos Vondar were blasted by that super battle droid on Drongar. Or the time she was infected by the brain worms while on a mission with Ahsoka Tano. Or the time she and Ahsoka were trapped under the piles of debris on Geonosis. Or that time on Ilum when the roof started falling down on her and her Master. Or the time Offee fought against Phow Ji on Drongar, and lost. Obviously, Offee went through a lot of near-death experiences while still young. She never stood a chance. And what's with the dark hood all the time? Obviously anti-social.
As you can see, all work and no play left Offee very dull. She was raised her whole life in the strict tenets of the Jedi Code. If you read any of the novels Offee is in, you will see that she had a very big vocabulary and was very smart... nerd. She was actually in Episode II: Attack of the Clones. You probably just didn't see her because she's one of those unimportant characters standing in the background. She fought in the Battle of Geonosis and actually survived, believe it or not, by finding an escape route.
Shocking Truth! Edit
Oh, noes, Barriss did not die during Order 66. She was arrested several days before, for organizing an act of terrorism in the Jedi Temple, because she was supposedly disillusioned in the Jedi Order. She was going all "Oh, the Jedi betrayed themselves, they are now warmongers and must be stopped" and all other kinds of Palpatine propaganda, while dual-wielding red lightsabers and using the Dark Side. Palpatine promptly put up a show, as if he was ordering to arrest and execute her. However, in truth, she was brought to Byss with much honor, completed her indoctrination and became the first Grand Inquisitor of the Empire.